I like that analogy about resentments, they really do hurt us more than they hurt anyone else.
I try to be aware of resentments as they build, because if I let them fester they will eat me alive.
I've been told the antidote to resentments is forgiveness, not condoning what was done or allowing it to happen again, but simply letting go of the pain related to it and leaving the rest to God. That helps me.
Hugs